| 摘要 |
PCT No. PCT/GB90/01417 Sec. 371 Date Mar. 25, 1992 Sec. 102(e) Date Mar. 25, 1992 PCT Filed Sep. 13, 1990 PCT Pub. No. WO91/04509 PCT Pub. Date Apr. 4, 1991.A single silica optical fiber (4) is formed in a Sagnac interferometer (2) by forming a fused, dichroic optical fiber coupler (8) having four ports (10, 12, 14 and 16). A 1.3 mu m optical data signal is coupled to the port (10) via a dichroic optical fiber coupler (18) which combines it with a 1.53 mu m c-w probe signal from laser (16). The coupler (8) splits the 1.53 mu m probe signal into two equal intensity, counter-propagating portions and couples the 1.3 mu m data signal so it propagates in one direction round the loop (6). The loop (6) exhibits a non-linearity such that the data signal provides a relative phase shift of the counter-propagating c-w probe portions causing a portion of the 1.53 mu m signal is switched to port (12). This 1.53 mu m switched output provides tapping of the data signal without affecting its intensity.
|
